Process for obtaining hydrochloric acid free from arsenic



Patented Feb. 2, 1926.

UNITED STATES. PATENT OFFICE.

ERWIN SCHMI DT, OF- HANNHEIM-WALDHOF, GERMANY, ASSIGNOR TO THE FIRM GESELLSCHAFT FUR CHEMISCHE PRODUKTION M. B. H., 01" HANNHEIM-WALDHOF, GERMANY, A CORPORATION OF GERMANY.

PROCESS FOR OBTAINING HYDROCHLORIC ACID FREE FROM ARS ENIC. i

No Drawing.

To all whom it may concern:

.Be it known that I, ERWIN SCHMIDT, a citizen of the German Republic, residing at Mannheim-Waldhof, in the Republic of Ger- 5 many, have invented new and useful I mprovements in a Process for Obtaining Hydrochloric Acid Free from Arsenic, of which the following is a specification.

Hitherto crude arsenic-containing hydrochloric acid was usually treated with sulphuretted hydrogen or barium sulphide, for the purpose of eliminating its arsenic.

It has been now discovered that it is easy to free completely crude ,arsenic-containing hydrochloric acid from its arsenic, whether the contents of the latter be relatively great or small, by treating it for a short time with activated charcoal. It has been found that charcoal manufactured by the process described in the U. S. Patent Ser. No. 1,358,162

November 9, 1920, of Knopflmacher isparticularly efiective. If for instance arsenic- Application filed May 2, 1924. Serial No. 710,619.

containing hydrochloric acid is shaken for a short time with a few per cent of the above charcoal from sulphite waste lye, and filtered, the filtrate will be found to be ab-v solutely free from arsenic. At the same time the hydrochloric" acid is also largely freed from iron which it generally contains,

so that a practically colourless acid is ob- Dz. 1m. ERW'IN SCHMIDT. 

